1. Field of the Invention
The invention relates generally to seismic energy detection and, more particularly, but not by way of limitation, it relates to a method and apparatus for detecting subsurface seismic energy propagation in air above the earth's surface.
2. Description of the Prior Art
While there are numerous types of seismic energy detectors utilized in contact with earth, either singly or in grouped arrays, for the purpose of detecting subterranean seismic energy emanations, the applicant knows of no prior art device which detects seismic energy through air coupling of the earth surface to a pressure responsive device. There are prior teachings of airborne seismic detectors, but these are directed to transport via helicopter, other aircraft or parachute for dropping and earth-coupling contact at a designated earth site. To applicant's knowledge, the concept of seismic energy detection through focusing and sensing air pressure variations at a point above the earth surface has not been heretofore utilized.